Method of sinking a shaft



UNITED STATES Search com PATENT OFFICE METHOD F SINKING A SHAFT JohnBranner Newsom, Nevada. City, Calif., as-

signor to Idaho Maryland Mines Corporation,

San Francisco, Calif.,

Application August 29,

8 Claims.

This invention relates to a mine shaft and has for its object theprovision of a method of sinking a mine shaft of any given diameter byprogressively enlarging a drilled shaft of relatively small diameterfrom the surface of the ground to any desired depth.

In carrying out this method a shaft of relatively small diameter isfirst drilled by the core drill shown in my United States Letters PatentNo. 2,090,304 of August 1'7, 1937. After this has been done the groundsurrounding the drilled shaft is divided into successive layers orbenches by drilling rings of bench holes into the ground. A bucket isthen secured and sealed within the drilled shaft below the level of thefirst bench, and dynamite or other exposive inserted into the benchholes dening the first bench and set oif, whereupon the ground formingthe first bench is made to drop into the bucket. Following this, thebucket is raised to the surface, its contents disposed of, and then itis lowered, secured and sealed within the drilled shaft below the nextsucceeding bench, whereupon the operation is repeated until the drilledshaft has been enlarged to the desired depth.

To illustrate my invention more clearly, reference is made to theaccompanying drawing, wherein:

Figure 1 is a vertical` section of drilled shaft showing successivelayers of benches formed by radially disposed bench holes.

Figure 2 is a section taken on the line 2-2 of Figure 1.

Figure 3 is a vertical section similar to that shown in Figure 1 butwith a bucket secured and sealed within the drilled shaft beneath theuppermost bench.

Figure 4 is a vertical section showing a drilled shaft and benchesformed by vertically disposed bench holes.

Figure 5 is a detail showing the method of sealing the bucket within thedrilled shaft.

Figure 6 is a vertical section taken through the lower portion of thebucket and showing the meansfor locking the bucket Within the drilledshaft'.

As briefly outlined above and as diagrammatically shown in Figures l, 2,Iand 3, a shaft l is first drilled to any desired depth, as for exampleby the core drill shown in my issued Patent No. 2,090,304. This havingbeen done, a series of platforms 2, 3, and 4, spaced about eight feetapart, is-lowered into the drilled shaft. Drillers standing on theseplatforms drill concentric rings of radially and upwardly extendingbench a corporation of Nevada 1938, Serial N0. 227,236

holes 5 into the ground surrounding the drilled shaft, for the purposeof defining layers or benches 6. The rings of holes 5 should be spacedabout two feet apart and the outer ends of the holes 5 shouldapproximately define the outer limits to which it is desired to enlargethe drilled shaft I. The drills used for drilling the holes 5 have beendiagrammatically indicated at l. A bucket 8 is then lowered into thedrilled shaft by the cable 9 and chains II to a point somewhat below therst bench B and sealed and secured therein. For the purpose of sealingthe bucket to the Walls of the drilled shaft I, resort may be had to aheavy rubber pneumatic tire l2 secured to the upper end of the bucketand provided with a heavily armored valve I3 by which it may be inflatedand deflated. In order to secure the bucket 8 in any desired positionwithin the shaft I, it is provided with a plurality of dogs I4 pivotedat its lower end I5. Attached to the outer ends of the dogs I4 aresprings I6, the upper ends of which are secured to cables Il passingupwardly through tubular guard members I8 formed in the walls of thebucket. By pulling up on the cables Il, the outer ends of the dogs I4are made to engage the walls of the drilled shaft I and any further loadplaced on the bucket will therefore tend to lock the bucket moresecurely in place. The bucket having been secured in its proper positionbelow the uppermost bench 6, the bench holes 5 are loaded with dynamiteor other exposive and then the explosive set off, thereby causing thematerial or ground forming the uppermost bench to fall into the bucket8. In passing, it should be noted that the dimensions of the bucket 8should be so correlated to the material contained in any particularlayer or bench of material that the bucket is at least 0f sucientcapacity to hold all of the material contained in any one bench.Preferably t'he bench holes defining any given bench are not firedsimultaneously but in rotation, so that only a small quantity of rockdrops into the bucket at one time. By following this procedure the shockto which the bucket is subjected is no more severe than the shockimposed on a skip when being loaded.

The bucket 8 with its contents is then raised to the surface, thecontents of the bucket disposed of, and then the bucket is again loweredinto the drilled shaft and secured and sealed immediately below thelevel of the next succeeding bench 6 so that the operation abovedescribed may be repeated. It will be seen that in this manner thedrilled shaft may be progressively enlarged by successively excavatingsuccessive layers or benches, and that in accordance with my methodlittle or no mucking is required.

While in the drawing the enlarged finished shaft has been shown ascircular in cross section, my process is just as applicable to theexcavation of shafts of any desired cross sectional form. All that isnecessary to vary the form is to vary the length of the bench holes soas to outline or dene the desired contour.

To carry out my method successfully, care must be taken to use cables 9and Il of sufficient strength to stand the abuse to which these membersare obviously subjected. Means such as, for example, shown in Figure 5may also be utilized to prevent excavated material from entering thespace between the bucket 8 and the drilled shaft I, for otherwise suchmaterial may become wedged between these two members and prevent thebucket 8 from being raised. Also means may be provided such as shown inFigure 6 for positively holding the bucket in any desired position.

In Figure 4, concentric rings of vertical bench holes 2| have beenshown. The formation of the ground being drilled will determine to alarge extent whether vertical or radially extending bench holes shouldbe used. If the lines of cleavage are vertical then it may be to greateradvantage to use vertical bench holes, while if the lines of cleavageare more generally horizontal, radial bench holes as shown in Figure 1can probably be used to better advantage. The arrangement shown inFigure 1 has the advantage that a considerable number of sets of benchholes may be simultaneously drilled by a multiple stage platform,whereas when vertical bench holes are used such as shown in Figure 4,only one series of bench holes can be drilled at any one time.

I claim:

1. The method of sinking a shaft of any given cross sectional area,comprising: drilling a substantially smooth-walled shaft of a diametersmaller than said given cross sectional area to any desired depth;progressively enlarging said drilled shaft to said given cross sectionalarea by blasting successive layers of the material surrounding saiddrilled shaft into a receptacle within said drilled shaft having anouter diameter only slightly smaller than the diameter of said shaft andlocated below the level of the particular layer being excavated; raisingsaid receptacle to the surface; removing its contents; and then loweringsaid receptacle within said drilled shaft to a level below the level ofthe next succeeding layer.

2. The method of sinking a shaft of any given cross sectional area,comprising: drilling a relatively smooth-walled shaft of a diametersmaller than said given cross sectional area to any desired depth;drilling a series of bench holes extending outwardly from the drilledshaft into the material surrounding said drilled shaft to define a layeror bench of said material; loading said bench holes with an explosive;excavating said bench by exploding the said explosive and allowing thebench material to fall Within a receptacle having an outer diameterslightly smaller than the diameter of said drilled shaft and locatedwithin said drilled shaft at a level below said bench; raising saidreceptacle and its contents to the surface; removing said contents; andthen repeating the cycle of operation until the cross sectional area ofsaid drilled shaft has been enlarged to any desired depth.

-3. The method of sinking a shaft of any given cross sectional area,comprising: drilling a substantially smooth-Walled shaft of a diametersmaller than said given cross sectional area ton any desired depth;drilling a plurality of series of bench holes extending outwardly fromthe drilled shaft into the material surrounding said drilled shaft toform superposed benches of said material; progressively excavating eachbench so formed by loading its bench holes with an explosive andblasting said bench into a receptacle having an outer diameter slightlysmaller than the diameter of said drilled shaft and located within saiddrilled shaft at a level below the bench being excavated; raising saidreceptacle and its contents to the surface; removing the contents ofsaid receptacle; and then positioning said receptacle within saiddrilled shaft below the level of the next succeeding bench.

4. The method of sinking a shaft of any given cross sectional area,comprising: drilling a substantially smooth-Walled shaft of a diametersmaller than said given cross sectional area to any desired depth;drilling bench holes into the material surrounding said drilled shaft todefine a bench of said material; lowering a receptacle of a diameterslightly smaller than the diameter of said drilled shaft into saiddrilled shaft to a position below said bench; loading said bench holeswith an explosive; excavating said bench by exploding said explosive andallowing the bench material to fall into said receptacle; raising saidreceptacle and its contents to the surface; removing the contents ofsaid receptacle; and then repeating the cycle of operation until thecross sectional area of said drilled shaft has been enlarged to anydesired depth.

5. The method defined in claim 4 including the steps of forming a sealbetween the upper edge of said receptacle and the adjacent wall of saiddrilled shaft prior to excavation of the bench; and the breaking of saidseal prior to the raising of said receptacle to the surface.

6. The method of sinking a shaft of any given cross sectional area,comprising: boring a shaft of a diameter smaller than said given crosssectional area to any desired depth; drilling a plurality of series ofbench holes extending outwardly from the bored shaft into the materialsurrounding said bored shaft to form. successive benches of saidmaterial; lowering a receptacle into said bored shaft to a positionbelow the level of the uppermost bench, forming a seal between the upperend of said receptacle and said bored shaft; excavating said uppermostbench by loading its bench holes with an explosive and blasting saidbench into said receptacle; breaking said seal; raising said receptacleand its contents to the surface; removing the contents of saidreceptacle; and then repeating the cycle of operation to successivelyremove said benches.

'7. The method of sinking a shaft of any given cross sectional area,comprising: drilling to any desired depth a substantially smooth-walledcylindrical shaft of a cross sectional area smaller than said givencross sectional area; excavating successive layers of materialsurrounding said drilled shaft into a receptacle having a diameter notsubstantially smaller than the diameter of said drilled shaft;supporting said receptacle by the side walls of said drilled shaft in aposition below the level of the particular layer to be excavated whilesaid layer is being excavated; raising said receptacle to the surface;and removing the contents from said receptacle.

8. The method of sinking a shaft of any cross sectional area,comprising: boring a shaft of a diameter smaller than said given crosssectional area to any desired depth; drilling bench holes into thematerial surrounding said bored shaft to define a bench of saidmaterial; lowering a receptacle into said bored shaft to a positionbelow said bench; obstructing the space between the rim of saidreceptacle and the adjacent wall of the bored shaft to prevent wedgingof material between said receptacle and said bored shaft; loading saidbench holes with an explosive; discharging said explosive to blast saidbench into said receptacle; removing said obstruction; and 5 raisingsaid receptacle and its contents to the surface.

JOHN BRANNER NEWSOM.

